Road structure and method for the production thereof

ABSTRACT

A method for producing a road structure, has the following steps: (i) applying a highly porous asphalt base layer onto a supporting structure, particularly applying a highly porous asphalt base layer onto a concrete structure; (ii) applying a reaction resin mix onto the highly porous asphalt base layer from step (i); (iii) applying a bonding agent onto the highly porous asphalt base layer from step (i), wherein the bonding agent is a thermoplastic which is solid at room temperature; (iv) applying a bitumen-based top layer.

TECHNICAL AREA

The invention relates to the area of the sealing of roads on a supporting structure.

PRIOR ART

Roads that are applied on a supporting structure, in particular on a concrete supporting structure, are frequently found, especially as bridges. Such concrete supporting structures can be sealed by highly porous asphalt supporting layers that are poured with reaction resin mixes. A bitumen-based top layer is customarily applied in street construction. However, the problem arises here that a good adhesive composite must be present between the top layer and material of the supporting structure, in particular the concrete, which naturally also comprises the adhering of all intermediate layers. In particular, the adhering between the highly porous asphalt supporting layer, poured with reaction resin mix, and the bituminous top layer poses a problem that is difficult to solve on account of the participating materials. If areas form during the application of the reaction resin mix on the highly porous asphalt supporting layer where the reaction resin mix forms rather large, cohesive areas on the upper side of the asphalt supporting layer, typically optically smooth areas from the reaction resin mixture, this is disadvantageous for a good adhesive composite. These areas result in a defective adhesive composite between the poured, highly porous asphalt supporting layer and the bituminous top layer.

PRESENTATION OF THE INVENTION

The present invention therefore has the problem of making a road structure available that can be readily and economically constructed and results in a good adhesive composite between the poured, highly porous asphalt supporting layer and the bituminous top layer, in particular at locations where the reaction resin mix forms rather large, cohesive areas on the upper side of the asphalt supporting layer.

It surprisingly turned out that this problem can be solved with the method according to claim 1, a road structure according to claim 11 and a use of an adhesive promoter according to claim 12. Furthermore, this method allows the road to be sealed on a supporting structure in particular on a concrete supporting structure in a rapid and cost-efficient manner.

Other aspects of the invention form subject matter of other independent claims. Especially preferred embodiments of the invention are subject matter of the dependent claims.

WAYS OF CARRYING OUT THE INVENTION

The present invention relates in a first aspect to a method of producing a road structure 1 comprising the steps

-   -   (i) Application of a highly porous asphalt supporting layer 3 on         a supporting structure 2, in particular the application of a         highly porous asphalt supporting layer 3 on a concrete structure         2;     -   (ii) Application of a reaction resin mix 4 on the highly porous         asphalt supporting layer 3 of step (i);     -   (iii) Application of an adhesive promoter 5 on the highly porous         asphalt supporting layer 3 of step (i), wherein the adhesive         promoter is a thermoplastic that is solid at room temperature;     -   (iv) Application of a bitumen-based top layer 6.

In a first step (i) a highly porous asphalt supporting layer 3 is applied on a supporting structure 2, in particular a concrete structure.

Such a supporting structure 2 is preferably a structure of above-ground or underground building construction. In particular, it can be a bridge, gallery, tunnel, an entry or exit ramp or a parking level. A bridge is considered a preferred example of such a supporting structure. This supporting structure necessary for the road is a structure of a material that can have a supporting function. In particular, this material is a metal or a concrete, in particular a reinforced concrete, preferably a steel concrete. A bridge of concrete is considered as the most preferred example of such a supporting structure.

The highly porous asphalt supporting layer 3 preferably consists of an Einkorn asphalt with a high pore volume, wherein, for example, asphalts of the classes 0/16, 0/11 or 0/5 can be used.

The highly porous asphalt supporting layer preferably has an adhesive promoter content of 4.5-7.5 wt %.

The highly porous asphalt supporting layer preferably has spherical or polyhedral pores limited by webs and forming a cohesive system. The term pores denotes in the present document hollow spaces that are conditioned by the production in and/or on the surface of a compound and that are filled with air or other substances foreign to compounding. The pores can be recognized or not by the naked eye. They are preferably open pores that communicate with the surrounding medium.

It is furthermore advantageous that the highly porous asphalt supporting layer has a pore size of 0.1-5 mm, in particular 0.2-1 mm and/or a pore volume of 5-90%, in particular 10-80%, preferably 20-40%. The term pore volume denotes in the present document the amount in percentage of the totality of the hollow spaces filled with air or other substances foreign to composition in the volume of the foamed composition. The thickness of the highly porous asphalt supporting layer is preferably 1-5 cm. It can furthermore be advantageous if the pore content of the highly porous asphalt supporting layer, measured in a Marshall body at 120° C., is between 15 and 30% by volume.

In another step (ii) a reaction resin mix 4 is applied on the highly porous asphalt supporting layer 3 from step (i). The application of the reaction resin mix preferably takes place while the highly porous asphalt supporting layer 3 has a temperature of 30° C.-60° C., in particular 30° C.-40° C.

The reaction resin mix preferably penetrates during the application into the highly porous asphalt supporting layer 3 and results by the subsequent hardening of the reaction resin mix in a seal, in particular against water, of the highly porous asphalt supporting layer 3 and in an adhesive composite of the highly porous asphalt supporting layer 3 with the supporting structure 2.

The reaction resin mix has a flowable consistency at room temperature and is typically applied by being brushed on, sprayed on or poured onto the highly porous asphalt supporting layer 3. It is to be noted that in this connection the term “flowable” denotes not only liquid but also highly viscous, honey-like to pasty materials whose shape is adapted under the influence of the gravitational force of the earth.

They are in particular two-component epoxide resin compounds, especially those whose one (i.e., first) component contains an epoxide resin, in particular an epoxide resin based on bisphenol-A-diglycidylether and the other (second) component contains a curing agent, especially a polyamine or a polymercaptan. Epoxide resin compounds are especially preferred that do not contain any fillers. Furthermore, the epoxide resin resin compounds are advantageously low-viscosity, in particular with a viscosity of below 10,000 mPas, preferably between 10 and 1,000 mPas so that they can penetrate into the highly porous asphalt supporting layer and if necessary into the supporting structure 2. Low-viscosity, two-component epoxide resin resin compounds are especially preferable as two-component epoxide resin resin compounds that are like those marketed under the trade series names Sikafloor®, Sikagard® or Sika Ergodur® of Sika Deutschland GmbH, or Sika Schweiz AG.

Flexiblized two-component epoxide resin resin compounds are especially preferred as two-component epoxide resin resin compounds. This is advantageous so that the reaction resin mix can carry out its sealing and compounding function even under high mechanical loads.

In another step (iii) an adhesive promoter 5 is applied on the highly porous asphalt supporting layer 3 in step (i).

The application preferably takes place by scattering the adhesive promoter in the form of pellets.

The application of the adhesive promoter preferably takes place in such a manner that 0.5-1.5 kg/m³, in particular 0.8-1.2 kg/m³ adhesive promoter are applied on the surface of the highly porous asphalt supporting layer.

The adhesive promoter is a thermoplastic that is solid at room temperature. The concept “room temperature” denotes a temperature of 23° C. The adhesive promoter preferably has a melting point of above 70° C., in particular between 100° C. and 180° C., preferably between 110° C. and 140° C. All melting points of polymers are measured in this document as softening points according to the ring-and-ball method according to DIN ISO 4625.

The adhesive promoter comprises in particular polyolefins, especially polyolefins that can be produced from the polymerization of ethylene with one or more unsaturated monomers. Such unsaturated monomers are in particular those monomers that are selected from the group consisting of propylene, butylene, butadiene, vinyl ester, especially vinyl acetate, maleic acid anhydride, acrylic acid, methacrylic acid, acrylic acid ester and methacrylic acid ester.

They are especially preferably polyolefins produced from the polymerization of ethylene with one or more unsaturated monomers selected from the group consisting of vinyl ester, especially vinyl acetate, maleic acid anhydride, acrylic acid, methacrylic acid, acrylic acid ester and methacrylic acid ester. They are preferably polyolefins that have a melting point above 60° C., in particular between 70° C. and 130° C.

It can furthermore be advantageous to use a mixture of the previously cited polyolefins. The amount of polyolefins is preferably 15-60 wt %, especially 20-40 wt % relative to the total weight of the adhesive promoter.

Furthermore, it can be advantageous if the adhesive promoter comprises a chemical expanding agent and/or a physical expanding agent. Chemical expanding agents are preferably organic or inorganic compounds that decompose under the influence of temperature, wherein at least one of the decomposition products is a gas. For example, compounds can be used as physical expanding agents that change into the gaseous aggregate state upon the elevation of the temperature. The adhesive promoter preferably comprises a chemical expanding agent.

Furthermore, it can be advantageous if the adhesive promoter comprises an epoxide solid resin. The amount of the epoxide solid resin is preferably 1-10 wt %, preferably 2-5 wt % relative to the total weight of the adhesive promoter.

Furthermore, it can be advantageous if the adhesive promoter comprises at least one resin that can be a natural resin or a synthetic resin. In particular, such resins are average- to higher-molecular compounds from the classes of paraffin resins, hydrocarbon resins, polyolefins, polyesters, polyethers, polyacrylates or amino resins. The resin preferably has a melting point or softening point between 60° C. and 140° C. In a preferred embodiment the resin is a hydrocarbon resin, in particular an aliphatic hydrocarbon resin. The resins are preferably resins with an average molecular weight of 1000-3000 g/mol. The amount of the resins is preferably 2-15 wt %, in particular 5-12 wt % relative to the total weight of the adhesive promoter.

Especially preferred adhesive promoters are adhesive promoters like those marketed under the commercial series names Sikalastic®-827 LT and Sikalastic®-827 HT of Sika Schweiz AG.

An application of an inorganic interspersing agent 7 on the highly porous asphalt supporting layer 3 of step (i) preferably takes place in a further step (v). This step is preferably carried out following the step (ii). This step is preferably carried out before the step (iii) or before the step (iv), in particular before the step (iii).

The inorganic interspersing agent 7 is especially sand, preferably quartz sand. In order to ensure a good composite between the interspersing agent and the reaction resin mix, it is advantageous if this interspersing agent is interspersed before the hardening of the reaction resin mix.

It is preferred if this inorganic interspersing agent has a maximum grain size less than 1 mm, in particular between 0.1 and 1 mm, preferably between 0.3 and 0.8 mm.

However, the amount of such interspersing agent is preferably dimensioned so that the surface of the highly porous asphalt supporting layer is not covered over the entire surface.

But, it can also be advantageous if the method has no step (v) with an application of an inorganic interspersing agent 7 on the highly porous asphalt supporting layer 3 from step (i). This is advantageous, among other things, since an increase of the adhesive compound, in particular of the breaking load and of the adhesive tensile strength results between the highly porous asphalt supporting layer poured with a reaction resin mix and a bitumen-based top layer.

In a further step (iv) a bitumen-based top layer 6 is applied.

This top layer 6 constitutes the road, that is in direct contact with vehicles. The bitumen-based top layer is heated before the application to a temperature of typically 140° C. to 160° C. and preferably rolled on with a roller. The application of the top cover is well known to a person skilled in the art and is therefore not discussed further here. In addition to bitumen, the top layer can comprise other possible constituents known to a person skilled in the art. A person skilled in the art well knows the type and amount of the constituents that are used for the construction of roads. The fact is especially important here that the top layer comprises mineral fillers, in particular sand or fine gravel, to a significant extent.

Upon the contacting of the molten bitumen with the adhesive promoter the adhesive promoter 5 partially melts or fuses as a function of its melting point. If it fuses, this can form a largely homogeneous layer of adhesive promoter—depending on the type of thermoplastic—or also dissolve in the bitumen in the vicinity of the surface and form a boundary phase layer containing adhesive promoter. Therefore, it is absolutely in the nature of the present invention that the adhesive promoter does not have to form an individual layer. If the adhesive promoter contains an expanding agent, the contacting of the fused bitumen preferably results in an activation of the expanding agent.

The road structure produced in this manner has the significant advantage that a good adhesive composite is ensured, in particular as regards the breaking load and the tensile strength between the highly porous asphalt supporting layer poured with a reaction resin mix and the bitumen-based top layer.

In another aspect the invention relates to a road structure produced according to the previously described method.

In another aspect the invention relates to the use of an adhesive promoter such as was previously described for increasing the adhesive composite, in particular the breaking load and the adhesive tensile strength between a highly porous asphalt supporting layer on a supporting structure and poured with a reaction resin mix and a bitumen-based top layer. The components required for this, in particular the adhesive promoter, supporting structure, reaction resin mix, asphalt supporting layer and bitumen-based top layer were already described in detail above.

FIG. 1 shows a possible result of the steps (i) and (ii). The applied reaction resin mix 4 is present for the most part in the pore spaces of the asphalt supporting layer 3. A cohesive area of reaction resin mix is visible on the surface of the asphalt supporting layer and can result in an optically smooth area on the asphalt supporting layer after the hardening of the reaction resin mix.

FIG. 2 shows a possible result of the steps (i) and (ii) as previously described in FIG. 1, wherein the step (v) was additionally carried out.

FIG. 3 shows a possible result of the steps (i), (ii), (iii) and (iv). The applied adhesive promoter 5 results in an improved adhesive composite of the asphalt supporting layer 3 with the top layer 6.

FIG. 4 shows a possible result of the steps in the sequence (i), (ii), (iii) and (iv). The applied adhesive promoter 5 results in an improved adhesive composite of the asphalt supporting layer 3 with the top layer 6.

List of Reference Numerals

-   1 road structure -   2 supporting structure, concrete supporting structure -   3 highly porous asphalt supporting layer -   4 reaction resin mix -   5 adhesive promoter -   6 bitumen-based top layer -   7 inorganic interspersing agent -   8 cohesive areas of reaction resin mix on the top side of the     asphalt supporting layer

EXAMPLES

Reaction resin mix (RH): STATIFLEX®-EP (Strabag).

Adhesive promoter (HM): Sikalastic®-827 LT (in the form of pellets with a size of approximately 2 mm)

A highly porous asphalt supporting layer STATIFLEX® (Strabag) (pore space content 25-30% by volume) with a thickness of approximately 2 cm was applied on concrete plates with a surface of 4400 cm², after which the still warm asphalt supporting layer (30-40° C.) was filled with the previously cited reaction resin mix (RH).

Quartz sand 2/5 mm was subsequently applied on the concrete plates of ex. 1.36 hours later a bitumen-based top layer was applied on the surface of the asphalt supporting layer containing the quartz sand.

Subsequently, approximately 1 kg/m3 of the previously cited adhesive promoter (HM) was uniformly applied on the concrete plates of ex. 2.36 hours later a bitumen-based top layer was applied on the surface of the asphalt supporting layer containing the adhesive promoter.

Quartz sand 2/5 mm was subsequently applied on the concrete plates of ex. 3. Subsequently, approximately 1 kg/m3 of the previously cited adhesive promoter (HM) was uniformly applied. 36 hours later a bitumen-based top layer was applied on the surface of the asphalt supporting layer containing the quartz sand and the adhesive promoter.

Drill cores d=100 mm were taken and adhesive pull tests carried out. The measured values listed in table 1 correspond to the average value of 3 measured values.

TABLE 1 measured values Breaking Adhesive pull load [KN] strength [N/mm²] Fracture image Ex. 1 0.9 0.21 Fracture between asphalt supporting layer and top layer Ex. 2 2.7 0.61 Fracture in top layer Ex. 3 2.5 0.57 Fracture in top layer 

1. A method for producing a road structure comprising the steps (i) Application of a highly porous asphalt supporting layer on a supporting structure; (ii) Application of a reaction resin mix on the highly porous asphalt supporting layer of step (i); (iii) Application of an adhesive promoter on the highly porous asphalt supporting layer of step (i), wherein the adhesive promoter is a thermoplastic that is solid at room temperature; (iv) Application of a bitumen-based top layer.
 2. The method according to claim 1, wherein the method also comprises a step (v) Application of an inorganic interspersing agent on the highly porous asphalt supporting layer from step (i).
 3. The method according to claim 1, wherein the highly porous asphalt supporting layer has a pore volume of 5-90%.
 4. The method according to claim 1, wherein the reaction resin mix is a two-component of epoxide resin resin compound.
 5. The method according to claim 1, wherein the adhesive promoter comprises polyolefins produced from the polymerization of ethylene with one or more unsaturated monomers selected from the group consisting of vinyl ester, maleic acid anhydride, acrylic acid, methacrylic acid, acrylic acid ester and methacrylic acid ester.
 6. The method according to claim 5, wherein the polyolefins have a melting point above 60° C.
 7. The method according to claim 5, wherein the amount of polyolefins is 15-60 wt %, relative to the total weight of the adhesive promoter.
 8. The method according to claim 1, wherein the adhesive promoter comprises a chemical expanding agent.
 9. The method according to claim 1, wherein the adhesive promoter comprises an epoxide solid resin.
 10. The method according to claim 1, wherein the adhesive promoter comprises at least one hydrocarbon resin.
 11. A road structure produced according to a method in accordance with claim
 1. 12. The method according to claim 1 further comprising, increasing the adhesive composite breaking load and the adhesive tensile strength between a highly porous asphalt supporting layer poured with a reaction resin mix and a bitumen-based top layer. 